Doctors give panda cub with crooked jaw a kiss of life

When orthodontist Long Hu was asked to fix a young patient's crooked jaw four years ago, he knew it would be particularly challenging, because the patient was unlike any other he had treated before.

The patient was Bei Xia, a male giant panda born in 2022 at the Chengdu Research Base of Giant Panda Breeding in Sichuan province, who suffered critical injuries shortly after birth and was left with a misaligned lower jaw. The cub — whose left forelimb also had to be amputated after birth following irreversible damage — was unable to latch on for suckling, which deprived him of adequate lifesaving nutrition.

When Bei Xia was six months old, Long's team decided to carry out an orthodontic correction — a procedure never performed on a giant panda. The treatment and rehabilitation, conducted by West China Hospital of Stomatology of Sichuan University, where Long works, in collaboration with the Chengdu base, took around six months.

A paper on the unusual medical case, which is the world's first, was recently published in the international journal The Angle Orthodontist.

According to the Chengdu base, Bei Xia was diagnosed with ischemic necrosis on his left forelimb — caused by hindered flow of oxygenated blood — after his inexperienced mother accidentally injured him while trying to pick him up with her mouth. The limb had to be amputated within hours of birth to save his life.

However, related injuries affected his mandible, or lower jaw bone. By the time he was three months old, the jawline asymmetry became so pronounced that veterinarians feared it would hinder his growth if not corrected. So they turned to Long's hospital, which is one of China's top institutions in its field.

Long, who led the orthodontic correction procedure, admitted it was a huge challenge. "Doctors knew almost nothing about how a panda's jaw develops, and there was very limited research available for reference," he said.

Veterinarians briefed the orthodontic team on a giant panda's oral anatomy, and there were several rounds of consultations before they settled on the best treatment plan.

"Giant pandas and humans are both mammals, and there are similarities in jaw development," Long said. "So we drew on our experience treating children — using external force to guide jaw growth."

The initial procedure took place at the panda base in early 2023 in an operation lasting several hours. Safety was a major challenge, veterinarians said. Anaesthesia is risky for wild animals, especially for panda cubs. Their low body weight leaves little margin for error, and their weak body temperature regulation demands precise control.

Doctors had to securely attach medical devices to the cub's teeth and apply traction with rubber bands, which keepers replaced every 24 hours over the next six months.

Bei Xia's jaw anomaly was largely corrected after the treatment, and his suckling, biting and swallowing functions returned to normal, according to the paper.

Hongxing News contributed to this story.

pengchao@chinadaily.com.cn